Science & Mathematics - 17 October 2007

.Butane is burned in a lighter. The formula for butane is C4H10.
a) Write the complete word equation for the combustion of butane: (4K)
Remember that oxygen must be present for combustion.
b) Write the unbalanced (skeleton) chemical equation for the combustion of butane: (4K)
c) Write the balanced chemical equation for the combustion of butane by adding the appropriate coefficients. (4K)
d) How many molecules of water are produced for every molecule of butane burned? (1K)

2007-10-17 06:06:08 · 2 answers · asked by Anonymous in Chemistry

Suppose you are standing on a weighing scale and all of a sudden the atmosphere vanished. The reading on the scale would
A) Quickly reduce to zero
B) Remain the same
C) Decrease (I selected but was incorrect)
D) Increase
E) None of the above

2007-10-17 06:05:06 · 8 answers · asked by jaxjagsfan19 1 in Astronomy & Space

4.5.3. Classify each word equation below, as one of the following: (10)
Combustion, Synthesis, Decomposition, Single Displacement, Double Displacement

a) carbonic acid à water + carbon dioxide
b) sulfur + oxygen à sulfur dioxide
c) iron + copper sulfate à iron sulfate + copper
d) silver nitrate + sodium chloride à sodium nitrate + silver chloride
e) aluminum + oxygen à aluminum oxide
f) water à hydrogen + oxygen
g) sodium sulfate + calcium chloride à calcium sulfate + sodium chloride
h) butane + oxygen à carbon dioxide + water
i) zinc + sulfuric acid à zinc sulfate + hydrogen gas
j) hydrogen chloride + ammonia à ammonium chloride

2007-10-17 06:02:55 · 1 answers · asked by Anonymous in Chemistry

2007-10-17 06:02:47 · 1 answers · asked by kelly m 1 in Chemistry

If I have negative velocity and I want to solve momentum question do I have to write negative sign of velocity in momentum formula or not like
V1M1+V1M2=V2M1+V2M2

2007-10-17 06:02:30 · 2 answers · asked by M R 1 in Physics

3, 5, 7, 9, 11

6, 9, 12, 15, 18

0, 3, 6, 9, 12

3, 6, 9, 12, 15

2007-10-17 05:59:41 · 5 answers · asked by Hamid K 1 in Mathematics

per year compounded annually. You plan to invest $3500 at the end of each year for the next 20 years. How much will your account have in it at the end of 20 years?

$130,520
$127,207
$128,750
$130,048

2007-10-17 05:58:21 · 2 answers · asked by Hamid K 1 in Mathematics

to practice for the test!

2007-10-17 05:57:42 · 1 answers · asked by Sara *Life is so unlike theory* 5 in Physics

does anyone know the answer to this?

2007-10-17 05:56:00 · 4 answers · asked by Theo d 1 in Mathematics

Somebody please help me in 1/2/2007 i saw a ufo in leeds, i told everybody and nobody bleves me


DO YOU

2007-10-17 05:53:33 · 11 answers · asked by Roman R 1 in Astronomy & Space

f(x) = -2x + 6 at ( 2, 2)

-6
6
-2
-1/2

2007-10-17 05:52:32 · 4 answers · asked by Hamid K 1 in Mathematics

How can this be accomplished when you can't divide by 0? Does the negative twelve make a difference?

2007-10-17 05:52:31 · 9 answers · asked by billiejosway2002 1 in Mathematics

I have three cats that stay in the living room.

Sometimes when I go out of the room, when I return, the cats are NOT in the same places they were when I left the room. Is this polar guy activity?

2007-10-17 05:51:44 · 17 answers · asked by Anonymous in Paranormal Phenomena

2007-10-17 05:48:45 · 1 answers · asked by Dave 2 in Chemistry

2007-10-17 05:46:44 · 7 answers · asked by justina k 1 in Physics

I keep hearing about these polar guys moving stuff and taking your keys. Who are they

2007-10-17 05:43:37 · 12 answers · asked by Miley 2 in Paranormal Phenomena

25 mg = ? hg A) 2500
25 cg = ? g B) .00025
25 g = ? dg C) 2.5
25 kg = ? dagD) .25
25 hg = ? kg E) 250

2007-10-17 05:40:52 · 1 answers · asked by Anonymous in Chemistry

2007-10-17 05:40:47 · 3 answers · asked by Anonymous in Mathematics

Find the heat of formation for a mole of hydrazine (N2H4) given:


2N2H4(l) + 2O2(g) → 2N2(g) + 4H2O(g) D Ho = -1068.4 kJ
H2(g) + 1/2O2(g) → H2O(g) D Ho = -241.8 kJ

2007-10-17 05:40:36 · 1 answers · asked by Anonymous in Chemistry

2007-10-17 05:40:06 · 7 answers · asked by justina k 1 in Botany

Why is the electric field between parallel plates uniform?
Appreciate the help :)

2007-10-17 05:38:49 · 4 answers · asked by Hannah 4 in Physics

Copper(I) oxide is oxidized to copper(II) oxide according to the following equation:
Cu2O(s) + 1/2O2(g) → 2CuO(s) [ΔHorxn = -146.0 kJ]
Given that ΔHf of Cu2O(s) = -168.6 kJ/mol.
What is ΔHf of CuO(s)?

2007-10-17 05:38:47 · 2 answers · asked by Anonymous in Chemistry

(a) KOH
(b) Ca(OH)2
(c) NaOH
(d) (Mg)2OH

2007-10-17 05:37:08 · 2 answers · asked by Jenn S 2 in Chemistry

im studying for a test and i was absent those days and the test is tommorrow !!

2007-10-17 05:36:33 · 3 answers · asked by Anonymous in Chemistry

2007-10-17 05:31:47 · 5 answers · asked by Anonymous in Physics

Calculate the mass of carbon that would be needed to reduce 15.9g of copper(II) oxide to copper by the reaction:
CuO+C ---> Cu+CO

thank you in advance.

2007-10-17 05:30:06 · 2 answers · asked by Roller 2 in Chemistry

Round the number .07535 to three significant figures.
.08
.0754
.0775
.07535

In which one of the following is the number correctly rounded to three significant figures?
3.2550.....>3.25
0.01832.....>0.018
100....>100
10.25....>10.3

2007-10-17 05:29:38 · 6 answers · asked by Anonymous in Chemistry

use of pythagoras theorm ,it's proofs

2007-10-17 05:29:15 · 2 answers · asked by vipul 1 in Mathematics

a. eukaryote-amoeba
b. ribosomes-protein
c. cell wall-animal cell
d. mitochondria-ATP

2007-10-17 05:26:40 · 3 answers · asked by ♥ 6 in Biology

This question is along with the first one I asked.

2007-10-17 05:25:55 · 3 answers · asked by Anonymous in Engineering